I just got a Kinect One to use with Windows MR for full body tracking and I spent almost an hour trying to find out why calibration would not work even if I moved accross the room. Turns out you had to be inside the white screen in SteamVR, there you could hear the applause when calibrating.
Since I was using the WIndows MR home to go to the desktop and start the calibration from there it wasn’t working for me.
Anyways, when you say that you can’t find full body tracking option you mean you don’t get this menu?
Are you on the latest Windows 10 update? Did you install the Kinect One SDK? If it’s installed you should be able to open the Kinect Studio 2.0 and click the connect button to see if your Kinect is working properly.
Otherwise, try another USB 3.0 port. I know that the Windows MR headsets already use 1 so it may not be possible but that fixed the problem for me, because for some reason the front 3.0 connectors wouldn’t let my Kinect One work properly although it did get recognized.